Fatigue Crack Assessment for Orthotropic Steel Deck Based on Compound Poisson Process
Haiping Zhang, Yang Liu, Yang Deng
Abstract
This study presents a crack propagation stochastic process model for orthotropic steel deck (OSD) based on the structural health monitoring (SHM) data. An inhomogeneous compound Poisson process model, which is integrated into four types of Poisson models, is proposed to describe the daily random traffic flow. The transient analysis was performed by the finite element model (FEM) to turn the vehicle load model into fatigue stress model. The OSD strain measured data and calculated data by the FEM were compared to verify the computational result. Then, the crack propagation model was deduced by combining the stress model and fracture mechanics. Furthermore, the fatigue crack growth rate under different vehicles load sequence and overload vehicles is discussed. The results show that the loading sequence, which is the higher vehicle load in the front of the row, causes more fatigue damage than do the other loading sequences. The crack propagation slowed down under the overloading vehicle, and an overload correction factor is proposed, with value as 0.804 for engineering applications in this study.